The present invention relates to reel-type slot machines, and more particularly to reel-type slot machines having multiple display reels each bearing a plurality of different game symbols, wherein the reels are driven to display game symbols corresponding to a game result randomly selected from repetitive sets of potential game results.
In recent years reel-type slot machines have evolved from mechanical type machines wherein mechanical clutches were relied on to stop spinning display reels at random locations to display a game result, to electronic type machines wherein a microprocessor randomly selects a game result, and the display reels are driven to reel positions wherein game symbols on the reels display the game result. The present invention is directed to an improvement in such an electronic type slot machine wherein a game result is randomly selected from repetitive sets of potential game results, and wherein the number of occurrences of a game result within the set determines the probability of that game result being selected. After selection of the game result, the reels are positioned to display the game symbols associated with the selected result.
In electronic reel type slot machines the reels are typically positioned by stepper motors, which may be contained in removable modules within the machine. The stepper motors respond to applied signals which are progressively phase-shifted relative to each other such that the stepper motors are caused to turn one element of rotation for each progression of the phase signals.
The phase signals are typically generated in motor drive circuits, which respond to applied motor stepping pulses to advance the reels in increments. The motor stepping pulses are generated by a microprocessor, a predetermined number of pulses being applied to the motor drive circuits to cause each motor to be incremented to a selected stopping position wherein the game result is displayed by the display reels. In prior slot machine designs, the stopping positions were typically determined by the microprocessor by either counting the number of motor pulses occurring after a "home" marker on the reel had passed a fixed sensor, or by counting markers provided on the reel for each symbol position after the home marker had passed.
In contrast, the present invention is directed to a reel-type slot machine wherein in response to a play command a random game result is selected, and the display reels are rotated to display the game symbols associated with that result.
Accordingly, it is a general object of the present invention to provide a new and improved reel-type slot machine.
It is a more specific object of the present invention to provide a reel-type slot machine wherein upon play a game result is randomly selected, and the display reels are driven by stepper motors to display the game symbols associated with the game result.
It is a still more specific object of the present invention to provide a reel-type slot machine wherein the game result is randomly selected from a repetitive set of potential game results, the number of occurrences of a game result in the set determining the probability of occurrence of the game result, and the reels are positioned to display the game symbols associated with the selected game result.